content: /*
   * Copyright 2017 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.reactive4javaflow.processors;
  
  import hu.akarnokd.reactive4javaflow.FolyamSubscriber;
  import hu.akarnokd.reactive4javaflow.fused.FusedSubscription;
  
  import java.util.concurrent.Flow;
  
  interface RefCountAddRemoveSupport<T> {
  
      boolean add(RefCountSubscriber<T> ps);
  
      void remove(RefCountSubscriber<T> ps);
  
      final class RefCountSubscriber<T> implements FolyamSubscriber<T>, FusedSubscription<T> {
  
          final FolyamSubscriber<? super T> actual;
  
          final RefCountAddRemoveSupport<T> parent;
  
          Flow.Subscription upstream;
  
          FusedSubscription<T> qs;
  
          RefCountSubscriber(FolyamSubscriber<? super T> actual, RefCountAddRemoveSupport<T> parent) {
              this.actual = actual;
              this.parent = parent;
          }
  
          @Override
          public void request(long n) {
              upstream.request(n);
          }
  
          @Override
          public void cancel() {
              upstream.cancel();
              parent.remove(this);
          }
  
          @Override
          public int requestFusion(int mode) {
              FusedSubscription<T> fs = this.qs;
              return fs != null ? fs.requestFusion(mode) : NONE;
          }
  
          @Override
          public T poll() throws Throwable {
              return qs.poll();
          }
  
          @Override
          public boolean isEmpty() {
              return qs.isEmpty();
          }
  
          @Override
          public void clear() {
              qs.clear();
          }
  
          @Override
          @SuppressWarnings("unchecked")
          public void onSubscribe(Flow.Subscription subscription) {
              upstream = subscription;
              if (subscription instanceof FusedSubscription) {
                  qs = (FusedSubscription<T>)subscription;
              }
              actual.onSubscribe(this);
          }
  
          @Override
          public void onNext(T item) {
              actual.onNext(item);
          }
  
          @Override
          public void onError(Throwable throwable) {
              actual.onError(throwable);
              parent.remove(this);
          }
  
          @Override
          public void onComplete() {
              actual.onComplete();
              parent.remove(this);
          }
      }
  
  }
  